The question of how much the Ob 3 weighs is one of the most pressing questions for anglers and hunters planning to buy a reliable aluminum boat, a model produced by the Novosibirsk Chkalov Aviation Plant that has earned a reputation for being “unkillable” and able to withstand the harsh conditions of Siberian rivers and lakes. build-up It remains the main factor influencing the choice of method of transportation and the power of the engine.
Understanding the actual weight of a boat is critically important in the planning phase of a purchase, and it depends on whether you can launch the boat alone, whether you need a trailer to transport it on public roads, and what kind of vehicle you need to use. boat-engine Often the numbers declared by the factory differ from the actual figures, especially if it is used copies or modifications with additional equipment.
In this article, we will conduct an in-depth analysis of weight specifications, analyze the influence of various factors on total weight and give practical tips for operation, you will learn why the weight of an empty body is not a final figure, and how to calculate correctly. loading capacity for safe navigation.
Design features and weight of the bodyThe Ob 3 is a welded aircraft aluminum structure that provides high strength at relatively low weight, and is designed to be monoplane with sharp contours, which makes you feel confident in the wave. The base weight of the hull, which is often indicated in technical passports, is of the order of magnitude. 230-240 kilogramsHowever, this value is only valid for a completely empty "block" without any additional equipment.
The actual mass of the case can vary depending on the year of production and the thickness of the metal used. Older specimens produced during the Soviet period often had a thicker sheet of aluminum, making them heavier than modern counterparts, but at the same time increasing their survivability. aluminum-alloy, used in production, has excellent corrosion resistance, but requires careful handling during welding and repair.
The hull has a complex geometry with welded zygomatic splashers and reinforced transoms. It is the outboard motor transom that adds a substantial mass to the structure. If you are planning a used boat, be sure to weigh it, because over the years of operation on the sides and bottom, a layer of fossils, paint or bitumen mastic could form, which will also increase the overall weight.
⚠️ Note: When buying used boat Ob 3, keep in mind that the weight can be increased by 15-20 kg due to previously applied anticorrosion coatings and residues of old glue or sealants.
Effect of modifications on total weightThere are several modifications of the boat Ob 3, and each of them has its own weight features. The basic version, known simply as Ob 3, is the lightest. Ob 3MThe cockpit is larger and the bow geometry is altered, and this change has resulted in an increase in body weight of about 10 to 15 kilograms compared to the base model.
Another important modification is the version with steering-consoleFactory versions were often equipped with built-in handbags and a control console, which significantly weighted the design. Installation of fiberglass or aluminum "headbone", steering (coil or hydraulic) and dashboard adds to the weight of another 30 to 50 kilograms.
It is also worth mentioning the modifications with stationaryAlthough Ob 3 was designed primarily for outboard motors, some owners have installed car engines with shafts inside the hull, a rework that drastically changes the center of gravity and increases the weight of the vessel by several hundred kilograms, making it unsuitable for transportation on a passenger trailer without special training.
How to distinguish Ob 3 from Ob 3M in appearance?
The main difference is the shape of the nose and the width of the cockpit: Ob 3M has a sharper nose, and the sides in the cockpit area are wider, which increases the usable area, and the M modification often changes the shape of the transom to install more powerful motors.
Weight in running order and with motorTo talk about the weight of a boat only in terms of the mass of the hull is to ignore the reality of exploitation. To be fully used on the water, you need to add the weight of the engine, fuel, oil, anchor gear and personal belongings to the hull. Outboard motor The Ob 3 requires a 30 to 50 hp engine to be smoothly glided.
The average weight of a modern two-stroke engine with a capacity of 30 hp is about 55-60 kg, and the four-stroke analogue is already about 80-90 kg. If you plan to install a 50 hp engine, then its weight can reach 95-105 kg depending on the manufacturer and the availability of an electric starter. Thus, only the body + motor already gives a load on the trailer about 300-340 kg.
Don't forget about it. fuel-tankA full 25-litre tank will add about 18-20 kg of weight (including the weight of the canister itself). If the tank is built in, its weight is already included in the design, but if you use remote tanks, they must be considered separately. The total weight of a equipped boat with an engine and a full tank often exceeds 350 kg, which requires a serious approach to the choice of trailer.
Transportation and trailer requirementsTransporting the Ob 3 over long distances is only possible with a car trailer. Given that the weight of the boat with the engine and equipment often exceeds 350 kg, a conventional passenger trailer may not fit or require modernization.
An important aspect is centreThe Ob 3 has a high side and a fairly heavy transom. If the trailer is not properly mounted (e.g., with a shift to the stern), there is a risk of the trailer wagging on the track. Proper loading assumes that the trailer's breather must be loaded at 10-15% of the total mass to ensure the stability of the coupling.
The mechanical winch itself weighs a little, but it adds a few kilograms to the bracket. Using an electric winch that makes life easier when you go down alone will add another 10-15 kilograms to the weight of the equipment on the trailer. All these little things add up to a significant increase.
☑️ Checking transport readiness
Comparison with peers and competitorsTo understand whether the Ob 3 weighs much or little, it is worth comparing it with popular analogues of aluminum and PVC. The main competitors in the class of metal boats are the Kazanka of various modifications and the Salyut. Kazanka-5M2, for example, weighs about 190 kg in the basic version, which makes it noticeably lighter than the Ob 3, but loses to it in seaworthiness and comfort on the wave.
Compared to the boats of the PVCThe difference is enormous. A 4.2-4.5 meter inflatable boat with a hard transom weighs about 100-120 kg with the engine and gear, which is three times less than a equipped Ob 3. However, PVC does not provide the protection from waves, speed and security that an aluminum hull gives.
Below is a table comparing the weight specifications of various modifications and analogues:
| Model boat | Body weight (kg) | Recommended motor power (hp) | Weight with 30 hp engine (kg) |
|---|---|---|---|
| Ob 3 (baseline) | ~230 | 25-40 | ~290 |
| Ob 3M | ~245 | 30-50 | ~310 |
| Kazankah-5M2 | ~190 | 20-35 | ~250 |
| Salute 450 | ~180 | 20-30 | ~240 |
⚠️ Attention: The motor weights shown in the table are averaged, and the exact weight depends on the specific engine model, the length of the lower unit and the availability of the electric starter.
Practical Tips for Weight Loss and OperationFor Ob 3 owners, who often face the problem of being overweight, there are several ways to optimize: the first and most obvious is to avoid unnecessary equipment; remove the engine if you plan to park for a long time or if there are no people in the boat; using removable handkerchiefs instead of built-in structures will also help reduce weight.
The second tip is storage. Aluminum tends to become overgrown with algae and shells, especially if the boat is in the water for a long time. Regular cleaning of the bottom not only improves driving performance, but also prevents weight gain. Use special anti-fouling coatings that are easy to wash off.
The third aspect is loadingTry to place heavy things (anchor, batteries, fuel supply) closer to the center of the boat or slightly closer to the nose to compensate for the weight of the motor on the transom, which will improve driving performance and reduce the risk of being overwhelmed by a wave through the transom.
Use lightweight composite anchors instead of traditional iron cats, which weigh 2-3 times less at the same holding power, saving you a few kilograms of total weight.
Optimal loading of the boat Ob 3 for planing is achieved by distributing the weight of passengers evenly along the sides and shifting the load slightly into the nose to unload the transom.
Frequently Asked Questions (FAQ)
Can I tow the boat Ob 3 without registration of the trailer?
According to traffic regulations, if the total mass of a trailer with a boat and engine exceeds 750 kg, the availability of category "E" and registration of the trailer is mandatory. If the total weight is less than 750 kg, category "B" rights are sufficient, but registration of a trailer with the traffic police is still required if its own weight exceeds 75 kg (which is almost always the case for a boat trailer).
Will the car withstand the towing Ob 3?
Yes, most passenger cars with an engine capacity of 1.6 liters and above are able to tow a trailer with Ob 3. However, it is important to consider the traction specifications of the engine and the presence of a farcope with a corresponding load on the ball (usually 50-75 kg).
How critical is excess weight for safety?
Exceeding the maximum permissible load capacity (indicated in the onboard plate, usually about 400-500 kg for Ob 3) is critically dangerous. The boat loses stability, the aft trifference increases, leading to flooding with the wave and possible rollover. Security It should always be a priority to take more weight.
Can you reduce the weight of Ob 3 by drilling holes?
It is strongly recommended not to drill additional holes in the bottom or sides to facilitate the design, this violates the tightness, reduces the rigidity of the body and creates foci for corrosion. Aluminum does not like unnecessary interference with the factory structure without professional argon welding.